You’ve just bought your first rifle scope, or maybe you’re looking at one online, and you’re faced with a string of numbers like 3-9×40 or 4-16×50. It looks like a secret code, and you’re left wondering how to crack it. This is a common first step for many new shooters and hunters, and it’s the key to choosing the right tool for the job.
Fortunately, this code is much simpler than it appears. Once you know what to look for, those numbers tell you everything you need about the scope’s magnification power and its ability to gather light. So, let’s break it down and answer the question: What Does The Numbers On A Rifle Scope Mean? [Simple Answer]
What Does The Numbers On A Rifle Scope Mean? [Simple Answer]
The numbers on a rifle scope describe its magnification and the size of its main lens. Let’s use the common scope designation “3-9×40” as our example. The first number, “3-9x,” tells you the magnification range. The “x” simply stands for “times.” So, this scope can magnify an image from 3 times (3x) up to 9 times (9x) its normal size. The second number, “40,” refers to the diameter of the objective lens in millimeters—that’s the lens at the very front of the scope.
Think of it like this: the numbers before the “x” are the zoom, and the number after the “x” is the size of the light-gathering window. A larger objective lens (like a 50mm instead of a 40mm) generally allows more light to enter the scope, which can result in a brighter image, especially in low-light conditions like dawn or dusk.
Breaking Down Magnification: Your Zoom Power
Magnification is often the first feature people consider. Scopes generally fall into three categories based on their magnification.
Fixed Power Scopes: You might see a scope labeled as “4×32.” This means it has a single, fixed magnification of 4 power. These scopes are simple, durable, and often very clear because they have fewer internal moving parts. They are excellent for consistent shooting at a known distance.
Variable Power Scopes: This is the most common type today. A scope marked “3-9×40” is a variable power scope. You can adjust the magnification from a low of 3x to a high of 9x by turning a ring, usually located near the eyepiece. This gives you incredible flexibility. You can use a low power for quick target acquisition on a close-range animal and then zoom to a higher power for a more precise shot at a longer distance.
High-Magnification Scopes: Scopes with designations like “6-24×50” are designed for long-range precision shooting. They offer a very high level of zoom, allowing you to see and aim at small targets hundreds of yards away. These are typically used by target shooters and long-range hunters.
The Objective Lens: Your Window to Light
The second number in the sequence is just as important as the first. The objective lens is the light-gathering element of your scope. A larger lens (e.g., 50mm vs. 40mm) can capture more light, which theoretically provides a brighter sight picture.
However, bigger isn’t always better. A larger objective lens requires the scope to be mounted higher on the rifle to clear the barrel, which can make it harder to get a consistent and comfortable cheek weld. It also adds weight and bulk to your setup. For most hunting situations in decent light, a 40mm or 44mm objective lens is perfectly sufficient.
Putting It All Together: A Practical Example
Let’s imagine you have two different scopes and two different hunting scenarios.
For a whitetail deer hunter in the wooded areas of the Eastern United States, shots are often quick and at relatively short ranges. A scope like a 2-7×32 or 3-9×40 would be an ideal choice. The lower magnification range (2x or 3x) provides a wide field of view, making it easy to spot a moving deer in thick cover. If the deer stops at a longer distance, you can quickly zoom up to 7x or 9x for a more precise aim.
For a prairie dog hunter or a long-range target shooter out West, shots can be extremely far. Here, a scope like a 6-24×50 makes more sense. The high magnification allows you to see a small target clearly at several hundred yards, and the large 50mm objective lens helps maintain a bright image even when you’re zoomed all the way in.
Other Numbers You Might See on a Scope
While the main numbers like 3-9×40 are the most critical, you’ll often find other markings. One of the most important is on the adjustment turrets—the knobs on the top and side of the scope. These are often marked with “UP” and “1/4 MOA” or “1/4″ at 100 yds.” This means that each click of the knob will move the point of impact by a quarter of a Minute of Angle at 100 yards, which is approximately a quarter of an inch. These turrets are used to adjust for wind and bullet drop at different distances.
In the end, those numbers on your rifle scope are a straightforward guide to its capabilities. The magnification range tells you how much you can zoom, and the objective lens size gives you an idea of its light-gathering potential. By matching these numbers to your specific shooting needs, you can select the perfect scope to help you shoot with more confidence and precision.